Party-line telephone.



PATENTED' MAY 23,1905.

"H. BASCOM. PARTY'LINB TELEPHONE.

APPLICATION IILISD SEPT. 12, 1904.

QXWfimeoow 331 ws Gua -L 1 a MW U ITED STATES Patented May 23, 1905.

PATENT ()FFICE.

HENRY MELVIN BASOOM, OF BROOKLYN, NEW YORK, ASSIGNOR TO JOHN F. HEMENWAY, OF NEWV YORK, N. Y.

PART'Y-LlNE'TELE PHONE.

SPECIFICATION forming part of Letters Patent No. 790,550, dated May 23, 1905.

Application filed September 12, 1904. SerialNo. 224,222. I

To all whom it may concern:

Be it known that I, HENRY MELVIN BAsooM, a citizen of the United States, residing at Brooklyn, New York, have invented new and useful Improvements in Party- Line Telephones, of which the following is a specification.

My invention relates to party-line telephones in which several instruments are connected in multiple across two branches of metallic lines.

It is one of the objects of my invention to construct a party-line in which any one of the telephone sets may be signaled without disturbing any of the other sets on the line and to accomplish this result with simple apparatus obtainable in the open market.

Another object of my invention is so to construct and connect the ringers or calling devices of the several substations that alternating currents proceeding from regular generators or generators used for calling and clear ing-out purposes will not signal any of the substations.

A further object of the invention is so to construct the system that while using a permanent ground connection at each substation the line will be perfectly balanced at all times relatively to the ground and no inductive disturbances will arise.

In general terms the invention includes a central station'and a series of substations, proper connections between the central and the substations, and means whereby a current may be sent from the central out on the line and cause the ringer of any predetermined substation to operate without aliecting th ringers of the other substations.

The invention also includes certain combinations of elements hereinafter fully described, and particularly pointedout in the claims.

Referring to the accompanying drawings, forming part hereof, and in which like reference characters refer to like parts throughout, Figure 1 is a diagrammatic view of a series of four substations and their connections, and Fig. 2 is a similar view of the central station.

In Fig. 1 of the drawings, 1, 2, 3, and 4 represent four substations supplied with ringers orsignaling devices R, R R and R", respectively, permanently bridged across the lines, each ringer being highly self-inductive and having suitable resistance. Each ringer consists of bells 1 and 5, having permanent electromagnets 6, carrying the legs 7 and 8. Each ringer is also supplied with a centrallypivoted armature 9, carrying a tongue 10, the armature being normally held biased by a spring 11.' It will be noted that the armatures at substations 1 and 2 are biased from left to right, while those at substations 3 and 4-. are biased from right to left. The purpose 01f this arrangement will hereinafter be made c ear.

The two branches of the metallic lines are represented by 12 and'13, having at each substation terminals 141: and 15, wound about the legs 7 and 8 of the electromagnets and terminating in the ground 16. The two legs of each ringer are oppositely wound, and the two terminals 14: of substations 2 and 3 are similarly connected to branch 12, while the two terminals 15 of the same substations are similarly connected to 13. The two terminals- 1 1 of substations 1 and 4: are similarly con' nected to branch 13, and the two terminals 15 of the same substations are similarly connected to the branch 12. The two coils of the legs or eleetromagnets of each ringer are wound to exactly the same resistance, and the middle points'between them are grounded, preventing any inductive disturbances from the ground. The lines 12 and 13 terminate at the central station in a jack J, having outer jack-springs 17 and 18 and inner springs 19' and 20 connected with thedrop 21.

The substations 1, 2, 3, and 4 are provided with alternating generators (of the kind known as cut-in G, G G and G", each generator having a spring 22 connected to the line 13,

a second spring 23 connected to the line 12,

a rotary shaft 24E, and a handle 25 for turning the shaft 24 and making contact'between the springs 22 and 23 for the'purposeof sending a current out on the lines. -Normally the springs 22 and 23 are out of contact.

The talking-circuits at the substationsnot being essential to illustrate the invention are not shown on the drawings.

Referring to Fig. 2 of the drawings, illustrating the central station, P and P represent two pulsating-current generators adapted to produce pulsating minus and plus currents, respectively, P being grounded at 26 and P at 27 on the side opposite the grounding of P. The keys for calling the various substations are indicated at K, K K and K", while C is the ringing-plug, having the tip C andC the answering-plug, supplied with the tip 0*. The drop forindicating that conversation is finished is represented by The contact-points for the keys are designated by 29, 30, 31, and 32.

The operation of the invention is made clear in the following: The ringers are polarized by the permanent magnets 6, all of the magnets preferably having the same pole turned in the same direction, and it may be assumed that the free end of each armature has a south polarity. If now a subscriber wishes to call central, the handle 25 of one of the generators is turned, causing the springs 22 and 23 to contact and an alternating current to traverse the branches 12 and 13, indicating a call at the drop 21 of the central. The current which is sent out from one of the substation-generators passes through the windings of all the ringers alternatelyin both directions between 12 and 13, and producing the same polarity in both legs 7 and 8 at the same time the armatures 9 will be unaffected and give no signal at the substations. A similar result occurs if one party-line is connected to a regular subseribers lineover the exchange and a clearing-out signal is given by the subscriber. When the conversation is completed, the signal to that effect will be indicated at the drop 28. If connection with substation 1 is desired, central inserts the plug 0 in the jack J and presses down the key K. This will close the circuit for a pulsating minus current from the ground 26 through the generator P, the contact 29, tip the jack-spring 17, line branch 12 to the terminals 15 of the ringers R and R and the terminals 14 of the ringers R and R and down to the ground 16 at each station.

As above stated, the free ends of all armatures 9 have a south pole, and the current which now enters the coils of leg 8 of the ringer R produces an intermittent north pole, thus attracting the armature 9 to the leg 8 and causing the bell to ring until the current is stopped. The same current passes down the coil of leg 7 of ringer R but inasmuch as the coil of leg7 on R is wound in an opposite direction to the winding of leg 8 of R the current will produce a south pole on leg 7 and the armature 9 of ringer R remains inert. The current further passes down the windings of leg 7 of ringer R and leg 8 of ringer 11*; but as the armatures 9 are held against these legs, respectively. it will be apparent that the current will be ineffective to ring the bells at stations 3 and at. The only bell, therefore, that will ring when a call from K at central is sent out is that of the '7 ringer R at the first substation.

Assuming a pulsating plus current to be sent out on the branch 12, by pressing the key K the current will traverse the same path as that just traced. It will enter the windings of leg 8 of ringer R and there produce an intermittent south pole, and the armature J also having a south polarity the ringer will not operate. In leg 7 of It the current will produce an intermittent north pole, attracting the armature which is of the opposite polarity and cause the bell to ring. No signals will be given at ringer R" and ringer It when the current enters the legs (coils) 7 and 8 thereof,because the armatures are held against legs by the action of the springs 11. Plus and minus pulsating currents sent over the branch 13 from generators I I by pressing keys K or K" will ring it or H." and will not affect the other ringers. are similar to those described in connection with stations 1 and 2 and the description need not be repeated.

From the foregoing description it will be The results here apparent that the principle upon which my invention is based is that only that ringer will operate under the influence of any particular current whose electromagnet or leg opposite the free end of the armature has or receives a polarity different from thatof the armature provided to give the signal.

The invention as herein described is obviously susceptible of many modifications, and I do not wish to be umlerstood as confining myself to the precise details shown in the drawings. Various kinds of ringers may be used and different combinations employed to produce the difference in polarity between the armature and the electromagnet, and such modifications I consider as within the scope of my invention.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. In a party-line telephone system, a central station, a series of four or more substations connected therewith, a two-part oppositely-wound electromagnet at each substation, an armature biased across each electromagnet, and means for attracting the armature of any predetermined electron'iagnet thereto, substantially as described.

2. In a party-line telephone system, a central station. a series of four or more substations connected therewith, a ringer at each substation comprising a two-part, oppositelywound electromagnet, an armature biased across each electron'iagnet, said armatures being biased in pairs in the same direction, and means for sending currents of different signs I from the central station, causing the attracas described.

3. In a-party-line telephone system, a central station, a series of four or more substations connected therewith, a ringer at each substation including a two-part electromagnet, the parts being oppositely wound and the windings thereof terminating centrally in the ground, a biased armature associated with each electromagnet, and means for giving the parts of the electromagnets different polarities and causing the armature to be attracted to that part of the electromagnet which has a polarity different from that of said armature, substantially as described.

4. In a party-line telephone system, a central station, a series of four or more substations connected therewith, a ringer at each substation including a two-part oppositelywound and'centrally-grounded electromagnet, a polarized armature associated with each electromagnet, one end of said armature being normally held out ofcontact with one part of the electromagnet by mechanical means, and means at the central station 'for sending out a current to polarize the electromagnet and attract the free end of the armature to that part of the electromagnet receiving a polarity different from that of the armature, substantially as described.

5. In a party-line telephone system, a central station, a series of four or more substations connected therewith, a ringer at each substation including a two-part electromagnet having the parts woundin opposite directions and to the same resistance and being centrally grounded, an armature for each electromagnet, and means for causing a predetermined ringer to operate by attracting the armature thereof to the corresponding electromagnet, substantially as described.

6. In a party-line telephone system, a central station, a series of substations connected therewith and in multiple across two metallic lines, and a generator at each substation also bridged across the lines, each substation having a ringer including a two-part electromag s net having the parts wound in opposite'directions and centrally grounded, whereby an alternating current proceeding from any substation-generator will operate a signal at the central station without operating the ringer at any'of the substations, substantially as described.

7. In a party-line telephone system, a central station, a series of substations connected therewith and in multiple across two metallic lines, and an alternating-current generator at each substation also bridged across the lines, each substation having a ringer including a two-part electromagnet with the parts wound in opposite directions and centrally grounded and a biased armature for each electromagnet bearing the sounder of the ringer, whereby the operation of the generator at any substation will produce a signal at the central station without signaling any of the substations, substantially as described.

8. In a party-line telephone system, the combination of a central station provided with generators for producing plus and minus pulsating currents, respectively, a series of four or more substations connected in multiple across two metallic lines proceeding from the central station to the substations, a ringer at each substation, comprising a two-part electromagnet, terminals from said lines wound to the same resistance about the parts of the electromagnet in opposite directions and grounded centrally of said parts, and an armature for each ringer, said armatures being adapted to be attracted to the electromagnets when the latter receive a polarity different from that of the armature, substantiallyas described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

HENRY MEL VIN BASCOM.

Witnesses;

PAUL NEUHUT, JOHN A. PERCIVAL. 

